Move to CSharpAuthor 1.1.1007 and drop the workarounds

[ipjohnson]

Three types in SourceGenerator.Impl.Utilities existed only because CSharpAuthor could not express what the interception writer needed. 1.1.1007 can, so they go — 515 lines deleted, 170 added.

removed	replaced by
ConstrainedTypeDefinition	ClassDefinition.WhereStatement
AccessorMemberDefinition	EventDefinition, PropertyDefinition.IndexParameters
TypeParameterDefinition	CSharpAuthor.TypeParameterDefinition

Two related hacks go with them. The state class no longer smuggles its type parameters through the class name — AddGenericParameter declares them — which in turn means the hand-built new ConstructorDefinition($"DmState{index}") can go back to AddConstructor(), since the name no longer carries <T> for the constructor to inherit. State classes are also sealed now, which ComponentModifier could not say before.

The local TypeParameterDefinition tests are deleted rather than moved: they covered a dependency's behaviour, and it is tested where it lives.

private sealed class DmState0<T> : global::…InvocationState<T> where T : class, new()
{
    public DmState0(Work_Intercepted self, T arg0)

The snapshots move, and it is worth reading why

1.1.1007 fixes stray indentation before a closing parenthesis, which this generator has been emitting on every single-argument invocation:

-  …DependencyRegistry<…>.Add(ModuleDependencies        );
+  …DependencyRegistry<…>.Add(ModuleDependencies);
-  …DependencyRegistry<…>.ApplyServices(services            );
+  …DependencyRegistry<…>.ApplyServices(services);

That is not interception-specific — it is all generated output from this library, which is why eight module snapshots move. I checked every diff across all of them normalises to whitespace before a closing paren and nothing else, so no semantics changed.

The API snapshot also shows the whole 1006→1007 CSharpAuthor delta, because that source is compiled into the analyzer assembly. That includes sealed/record/init/file-scoped-namespace support which was already on their main before any of this work.

Verification

385 tests pass (400 minus the 15 deleted duplicates), 0 warnings, 86.9% coverage, verify-packages.sh clean. Generated output inspected directly for the generic state class, the event, and the multi-index indexer.

🤖 Generated with Claude Code

https://claude.ai/code/session_01EgLfDy82CnQZiuU5j8byu9